This invention relates to a powertrain including an electric motor generator and to the manner of mounting the generator rotor.
U.S. Pat. No. 5,103,127 Peter, assigned to the assignee of the present invention, describes a torque converter mounted starter/generator for a motor vehicle in which the rotor of the starter/generator machine is formed on the outer circumference of an input shell of a vehicle torque converter. The arrangement provides a compact assembly but substantially increases the complexity of the combined torque converter shell and generator rotor.
U.S. Pat. No. 6,208,036 Evans et al., commonly assigned, describes a vehicle powertrain with integrated motor generator wherein the generator rotor and the vehicle torque converter shell are independently connected with an engine crankshaft with the generator rotor essentially surrounding the torque converter. This arrangement substantially reduces manufacturing complexity although the difficulty of assembling the transmission and converter assembly to the engine is somewhat increased.
An improved arrangement providing both manufacturing simplicity and relative ease of assembly is accordingly desired.
The present invention provides an improved powertrain including a rotary input member such as an engine crankshaft, a torque coupling such as a hydraulic torque converter, a drive plate such as an automotive flex plate or connecting spider, and an annular generator rotor at least partially surrounding the torque coupling and connected with the coupling and the drive plate by a mounting ring forming a part of the rotor. The generator rotor includes an electrical power annulus, such as an annular induction member, and the mounting ring which is fixed to the power annulus for supporting the annulus and connecting it with the coupling and the drive plate.
In a preferred embodiment, the generator rotor is of the induction motor or generator type, although other forms of generator rotors could be utilized with the invention. The mounting ring, which forms a part of the generator rotor and supports the electrical power annulus, preferably includes two integral portions, namely an annular support and an annular connector. The annular support is a cylindrical portion on which the power annulus is mounted in any suitable manner, such as by a shrink fit. The annular connector may be formed as an inwardly directed flange which includes a plurality of openings for connection of the mounting ring with the converter and with the mounting plate.
Three examples of mounting ring configurations are disclosed including an angle ring, a T-ring and a C-ring, all referring to cross-sectional configurations of the various ring embodiments. In the angle ring, the annular connector or flange extends more or less radially inward from one end of the annular support or cylindrical portion. In the T-ring, the flange extends inward from a point between the ends of the cylindrical portion but closer to one end, and in the C-ring, the flange extends inward from the one end of the cylindrical portion.
In the angle ring and the T-ring, the flange is generally provided with three, or more, equiangularly-spaced openings which mate with openings in the drive plate and with drive lugs on the front of the torque converter shell. A peripheral flange on the drive plate may be used to assist in aligning the components during assembly. The drive plate is connected with both the generator rotor and the torque converter by bolts inserted through the three spaced openings in the flange and threaded into recesses in the torque converter lugs.
In the case of the C-ring, the flange is provided with two groups of three, or more, equiangularly-spaced openings alternating with one another around the ring. A first group has threaded nuts tack welded to the interior of the flange and bolts are inserted therein from the front or input member side of the drive plate to connect the rotor with the drive plate. A re-entrant rim on the interior edge of the flange guides on the torque converter lugs and assists in aligning the torque converter shell with the rotor during assembly of these components.
The mounting ring is connected to the converter lugs through the second alternate group of three, or more, openings in the mounting ring flange through which additional bolts are inserted from the input member or crankshaft side of the mounting plate through the mounting ring openings into threaded openings in the converter lugs. The arrangement simplifies connection of the generator rotor to the torque converter when the transmission is assembled to the engine.